Intial commit of CBS to ONAP

Change-Id: I2082544efc59476ac8de0dc39c899f968c3847bd
Signed-off-by: Tommy Carpenter <tommy@research.att.com>
Issue-Id: DCAEGEN2-47

4 files changed, 315 insertions, 0 deletions

diff --git a/config_binding_service/__init__.py b/config_binding_service/__init__.py
new file mode 100644
index 0000000..51d3246
--- /dev/null
+++ b/config_binding_service/__init__.py
@@ -0,0 +1,52 @@
+# ============LICENSE_START=======================================================
+# org.onap.dcae
+# ================================================================================
+# Copyright (c) 2017 AT&T Intellectual Property. All rights reserved.
+# ================================================================================
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+# 
+#      http://www.apache.org/licenses/LICENSE-2.0
+# 
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============LICENSE_END=========================================================
+#
+# ECOMP is a trademark and service mark of AT&T Intellectual Property.
+import os
+import logging
+
+'''Configures the module root logger'''
+root = logging.getLogger()
+if root.handlers:
+    root.handlers.clear()
+formatter = logging.Formatter('%(asctime)s | %(name)s | %(module)s | %(funcName)s | %(lineno)d |  %(levelname)s | %(message)s')
+handler = logging.StreamHandler()
+handler.setFormatter(formatter)
+root.addHandler(handler)
+root.setLevel("DEBUG")
+
+class BadEnviornmentENVNotFound(Exception):
+    pass
+
+def get_logger(module=None):
+    '''Returns a module-specific logger or global logger if the module is None'''
+    return root if module is None else root.getChild(module)
+
+def get_consul_uri():
+    """
+    This method waterfalls reads an envioronmental variable called CONSUL_HOST
+    If that doesn't work, it raises an Exception
+    """
+    if "CONSUL_HOST" in os.environ:
+        # WARNING! TODO! Currently the env file does not include the port.
+        # But some other people think that the port should be a part of that.
+        # For now, I'm hardcoding 8500 until this gets resolved. 
+        return "http://{0}:{1}".format(os.environ["CONSUL_HOST"], 8500)
+    else:
+        raise BadEnviornmentENVNotFound("CONSUL_HOST")
+
diff --git a/config_binding_service/client.py b/config_binding_service/client.py
new file mode 100644
index 0000000..02354ee
--- /dev/null
+++ b/config_binding_service/client.py
@@ -0,0 +1,181 @@
+# ============LICENSE_START=======================================================
+# org.onap.dcae
+# ================================================================================
+# Copyright (c) 2017 AT&T Intellectual Property. All rights reserved.
+# ================================================================================
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+# 
+#      http://www.apache.org/licenses/LICENSE-2.0
+# 
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============LICENSE_END=========================================================
+#
+# ECOMP is a trademark and service mark of AT&T Intellectual Property.
+import re
+import requests
+import copy
+import base64
+import json
+import six
+from config_binding_service import get_consul_uri, get_logger
+from functools import partial, reduce
+
+_logger = get_logger(__name__)
+CONSUL = get_consul_uri()
+
+template_match_rels = re.compile("\{{2}([^\}\{]*)\}{2}")
+template_match_dmaap = re.compile("<{2}([^><]*)>{2}")
+
+###
+# Cusom Exception
+###
+class CantGetConfig(Exception):
+    def __init__(self, code, response):
+        self.code = code
+        self.response = response
+###
+# Private Functions
+###
+def _consul_get_key(key):
+    """
+    Try to fetch a key from Consul. 
+    No error checking here, let caller deal with it
+    """
+    _logger.info("Fetching {0}".format(key))
+    response = requests.get("{0}/v1/kv/{1}".format(CONSUL, key))
+    response.raise_for_status()
+    D = json.loads(response.text)[0]
+    return json.loads(base64.b64decode(D["Value"]).decode("utf-8"))
+
+def _get_config_rels_dmaap(service_component_name):
+    try:
+        config = _consul_get_key(service_component_name) #not ok if no config
+    except requests.exceptions.HTTPError as e:
+        #might be a 404, or could be not even able to reach consul (503?), bubble up the requests error
+        raise CantGetConfig(e.response.status_code, e.response.text)
+
+    rels = []
+    dmaap = {}
+    try: #Not all nodes have relationships, so catch the error here and return [] if so
+        rels = _consul_get_key("{0}:rel".format(service_component_name))
+    except requests.exceptions.HTTPError: #ok if no rels key, might just have dmaap key
+        pass
+    try:
+        dmaap = _consul_get_key("{0}:dmaap".format(service_component_name))
+    except requests.exceptions.HTTPError: #ok if no dmaap key
+        pass
+    return config, rels, dmaap
+
+def _get_connection_info_from_consul(service_component_name):
+    """
+    Call consul's catalog
+    TODO: currently assumes there is only one service
+
+    TODO: WARNING: FIXTHIS: CALLINTHENATIONALARMY:
+    This tries to determine that a service_component_name is a cdap application by inspecting service_component_name and name munging. However, this would force all CDAP applications to have cdap_app in their name. A much better way to do this is to do some kind of catalog_lookup here, OR MAYBE change this API so that the component_type is passed in somehow. THis is a gaping TODO. 
+    """
+    _logger.info("Retrieving connection information for {0}".format(service_component_name))
+    res = requests.get("{0}/v1/catalog/service/{1}".format(CONSUL, service_component_name))
+    res.raise_for_status()
+    services = res.json()
+    if services == []:
+        _logger.info("Warning: config and rels keys were both valid, but there is no component named {0} registered in Consul!".format(service_component_name))
+        return None #later will get filtered out
+    else: 
+        ip  = services[0]["ServiceAddress"]
+        port = services[0]["ServicePort"]
+        if "cdap_app" in service_component_name:
+            redirectish_url = "http://{0}:{1}/application/{2}".format(ip, port, service_component_name)
+            _logger.info("component is a CDAP application; trying the broker redirect on {0}".format(redirectish_url))
+            r = requests.get(redirectish_url)
+            r.raise_for_status()
+            details = r.json()
+            # Pick out the details to expose to the component developers. These keys come from the broker API
+            return { key: details[key] for key in ["connectionurl", "serviceendpoints"] }
+        else:
+            return "{0}:{1}".format(ip, port)
+    
+def _replace_rels_template(rels, template_identifier):
+    """
+    The magic. Replaces a template identifier {{...}} with the entrie(s) from the rels keys
+    NOTE: There was a discussion over whether the CBS should treat {{}} as invalid. Mike asked that 
+    it resolve to the empty list. So, it does resolve it to empty list.
+    """
+    returnl = []
+    for r in rels:
+        if template_identifier in r and template_identifier is not "":
+            returnl.append(r)
+    #returnl now contains a list of DNS names (possible empty), now resolve them (or not if they are not regustered)
+    return  list(filter(lambda x: x is not None, map(_get_connection_info_from_consul, returnl)))
+
+def _replace_dmaap_template(dmaap, template_identifier):
+    """
+    This one liner could have been just put inline in the caller but maybe this will get more complex in future
+    Talked to Mike, default value if key is not found in dmaap key should be {}
+    """
+    return {} if (template_identifier not in dmaap or template_identifier == "<<>>") else dmaap[template_identifier]
+
+def _replace_value(v, rels, dmaap):
+    """
+    Takes a value v that was some value in the templatized configuration, determines whether it needs replacement (either {{}} or <<>>), and if so, replaces it.
+    Otherwise just returns v
+    
+    implementation notes:
+    - the split below sees if we have v = x,y,z... so we can support {{x,y,z,....}}
+    - the lambda is because we can't fold operators in Python, wanted fold(+, L) where + when applied to lists in python is list concatenation
+    """
+    if isinstance(v, six.string_types): #do not try to replace anything that is not a string
+        match_on_rels = re.match(template_match_rels, v)
+        if match_on_rels:
+            template_identifier = match_on_rels.groups()[0].strip() #now holds just x,.. of {{x,...}}
+            rtpartial = partial(_replace_rels_template, rels)
+            return reduce(lambda a,b: a+b, map(rtpartial, template_identifier.split(",")), [])
+        match_on_dmaap = re.match(template_match_dmaap, v)
+        if match_on_dmaap:
+            template_identifier = match_on_dmaap.groups()[0].strip()
+            """
+            Here is what Mike said:
+                1) want simple replacement of "<< >>" with dmaap key value
+                2) never need to support <<f1,f2>> whereas we do support {{sct1,sct2}}
+                The consequence is that if you give the CBS a dmaap key like {"foo" : {...}} you are going to get back {...}, but rels always returns [...].
+                So now component developers have to possible handle dicts and [], and we have to communicate that to them
+            """
+            return _replace_dmaap_template(dmaap, template_identifier)
+    return v #was not a match or was not a string, return value as is
+
+def _recurse(config, rels, dmaap):
+    for key in config:
+        v = config[key]
+        if isinstance(v, list):
+            replacement = [_recurse(item, rels, dmaap) for item in v]
+        elif isinstance(v,dict):
+            replacement = _recurse(v, rels, dmaap)
+        else:
+            replacement = _replace_value(config[key], rels, dmaap)
+        config[key] = replacement
+    return config
+
+#########
+# PUBLIC API
+#########
+def resolve(service_component_name):
+    """
+    Return the bound config of service_component_name
+    """
+    config, rels, dmaap = _get_config_rels_dmaap(service_component_name)
+    _logger.info("Fetching {0}: config={1}, rels={2}".format(service_component_name, json.dumps(config), rels))
+    return _recurse(config, rels, dmaap)
+
+def resolve_override(config, rels=[], dmaap={}):
+    """
+    Explicitly take in a config, rels, dmaap and try to resolve it.
+    Useful for testing where you dont want to put the test values in consul
+    """
+    #use deepcopy to make sure that config is not touched
+    return _recurse(copy.deepcopy(config), rels, dmaap)
diff --git a/config_binding_service/controller.py b/config_binding_service/controller.py
new file mode 100644
index 0000000..a74d60f
--- /dev/null
+++ b/config_binding_service/controller.py
@@ -0,0 +1,49 @@
+# ============LICENSE_START=======================================================
+# org.onap.dcae
+# ================================================================================
+# Copyright (c) 2017 AT&T Intellectual Property. All rights reserved.
+# ================================================================================
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+# 
+#      http://www.apache.org/licenses/LICENSE-2.0
+# 
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============LICENSE_END=========================================================
+#
+# ECOMP is a trademark and service mark of AT&T Intellectual Property.
+from config_binding_service import client, get_consul_uri, get_logger
+import requests
+from flask import request,  Response
+import json
+
+def bind_config_for_scn(service_component_name):
+    try:
+        bound = client.resolve(service_component_name)
+        return Response(response=json.dumps(bound),
+                       status=200, 
+                       mimetype="application/json")
+    except client.CantGetConfig as e:
+        return Response(status=e.code,
+                        response=e.response)
+    except Exception as e: #should never happen...
+        _logger.error(e)
+        return Response(response="Please report this error",
+                        status=500)
+
+def healthcheck():
+    #got this far, I must be alive... check my connection to Consul by checking myself
+    CONSUL = get_consul_uri()
+    res = requests.get("{0}/v1/catalog/service/config_binding_service".format(CONSUL))
+    if res.status_code == 200:
+        return Response(response = "CBS is alive and Consul connection OK",
+                        status = 200)
+    else:
+        return Response(response = "CBS is alive but cannot reach Consul",
+                        status = 503)
+
diff --git a/config_binding_service/swagger/swagger.yaml b/config_binding_service/swagger/swagger.yaml
new file mode 100644
index 0000000..208e441
--- /dev/null
+++ b/config_binding_service/swagger/swagger.yaml
@@ -0,0 +1,33 @@
+---
+swagger: "2.0"
+info:
+  version: "1.0.0"
+  title: "Config Binding Service"
+paths:
+  /service_component/{service_component_name}:
+    parameters:
+      - name: "service_component_name"
+        in: "path"
+        description: "Service Component Name. service_component_name and  service_component_name:rels must be keys in consul."
+        required: true
+        type: "string"
+    get:
+      description: "Binds the configuration for service_component_name and returns the bound configuration as a JSON"
+      operationId: "config_binding_service.controller.bind_config_for_scn"
+      responses:
+        200:
+          description: OK; the bound config is returned as an object
+          schema: 
+            type: object
+        404:
+          description: there is no configuration in Consul for this component
+  /healthcheck:
+    get:
+      description: "This is the  health check endpoint. If this returns a 200, the server is alive and consul can be reached. If not a 200, either dead, or no connection to consul"
+      operationId: "config_binding_service.controller.healthcheck"
+      parameters: []
+      responses:
+        200:
+          description: Successful response
+        503:
+          description: the config binding service cannot reach Consul